Proposals requested for 2019 Kaiser Conservation Endowment
Proposals are now being accepted to the Kaiser Conservation Endowment to fund small projects for promotion and demonstration of conservation practices targeting soil erosion. Application deadline is January 23, 2019.
Proposals are sought that fund the training of college and K-12 students and constituents, including curriculum development, field trips, teaching aids, audio/visual or other education-related activities. Funds are open to Washington State University, University of Idaho, Natural Resource Conservation Service (NRCS), Conservation Districts, and colleges in Washington and Idaho. However, proposals must have a strong linkage to WSU, the University of Idaho, Conservation Districts, and/or NRCS. Funds are limited to the Inland Empire – the area east of the Washington Cascades and north of the Salmon River in Idaho.
Successful 2018 applicants should attach a progress report to any new or continuing proposal.
Proposals are not to exceed $5,000. Up to three grants will be awarded for this current funding cycle. Instructions for proposal format can be found on the Kaiser Conservation Endowment page.
Northwest Rangelands – Where Do our Climate Vulnerabilities Lie?
What will climate change look like on Pacific Northwest rangelands, which cover a huge area of our region? It will undoubtedly have complex impacts on the physical environment, environmental stressors, socio-economic factors, and the animals, plants, and other rangeland organisms. Recently, I took a look at the literature to see what the state of the science is relating to rangelands’ vulnerability to climate change. While there are a number of relevant studies that I mention below, I focus in this article on one of the few quantitative analyses, led by Matt Reeves, that updates Reeves’ previous work that was discussed on agclimate.net.
In the Pacific Northwest, net primary productivity, which determines forage availability, is likely to increase by mid-century (with increases also expected in the Northern Plains region and decreases in the Southwest and Southern Plains) (Reeves et al. 2017; green in Figure 1A). Other scientific teams using different methods have suggested similar impacts. This increase in productivity is likely to benefit Northwest ranchers, especially when considered in light of the decreases in productivity in more southern regions.
However, increases in productivity are accompanied by higher variability from year to year in many areas (red in Figure 1B), which will likely exacerbate challenges for cow-calf operations, as unexpectedly destocking in response to reduced forage production can create economic losses, and increasing herd size in response to higher-than-expected forage production generally takes more than a year (Neibergs et al. 2017). However, in a few areas of the Pacific Northwest, variability could decrease (green in Figure 1B).
Meanwhile, across the western U.S., the same study projected a move from woody dominance toward grassier vegetation types overall but with considerable variation across the region. However, these projections assumed no fire suppression occurs. It remains to be seen whether fire suppression efforts will actually lessen, perhaps as climate change leads to larger and more intense fire events. Other research teams have suggested that climate does not have a large impact on whether or not woody species dominate, and that grazing history, fire regime, and soil type will continue to be determining factors (Polley et al. 2013). Rangeland vegetation is also likely to shift in response to climate change’s interactions with the potential for threats from invasive grasses like cheatgrass (Bromus tectorum), medusahead (Taeniatherum caput-medusae) and red brome (Bromus rubens) (Polley et al. 2013). This in turn could reduce forage quality and also contribute to larger and more frequent fires.
Last, Reeves’ results indicated a substantial increase in the number of heat-stress days for cattle across all regions beginning as early as 2020-2030 (red in Figure 2), including for areas of the Pacific Northwest that do not currently experience much heat stress. It is important to recognize that the heat stress data represented here are relative to the baseline period of 2001 – 2010, during which there were only a few cattle heat-stress days per year. In this region, the number of heat stress days by mid-century are projected to exceed 60 days annually in the A2 scenario. This may create a substantial need for adaptive strategies.
It is almost certain that ongoing climate change will substantially impact both cattle operations and the complex ecosystems that make up Pacific Northwest rangelands. Impacts in other regions are also likely to be very important for the Pacific Northwest, as these impacts will affect livestock economics across the U.S. The Southern Plains—with the current highest beef cow inventory—and the Southwest regions are projected to be negatively impacted for most indicators relevant to rangeland livestock production, rather than some indicators pointing to negative impacts and some to positive impacts, as in the Northwest. Relative advantages may thus shift to the Northern Plains and Northwest regions, despite some important challenges here.
Neibergs, J.S., T.D. Hudson, C.E. Kruger, and K. Hamel-Rieken. 2017. Estimating climate change effects on grazing management and beef cattle production in the Pacific Northwest. Climatic Change DOI 10.1007/210584-017-2014-0.
Polley, H.W., D.D. Briske, J.A. Morgan, K. Wolter, D.W. Bailey, and J.R. Brown. 2013. Climate change and North American Rangelands: Trends, projections, and implications. Rangeland Ecology & Management, 66(5): 493-511.
Reeves, Matt C.; Bagne, Karen E.; Tanaka, John. 2017. Potential climate change impacts on four biophysical indicators of cattle production from western US rangelands. Rangeland Ecology and Management. 70(5): 529–539. www.bioone.org/doi/full/10.1016/j.rama.2017.02.005
Learning from some of the first adopters of high residue farming in the Columbia Basin
Topsoil has often been referred to as the “thin skin” of our planet, essential for producing the food that feeds us. Because it’s not easy to create new topsoil, conserving the soil that we have is essential for maintaining our region’s agricultural productivity. Reducing tillage, and leaving residue on the soil surface, is a proven way to reduce erosion. As residues break down, they increase the concentration of soil organic matter at the surface of the soil and help to form soil aggregates—a composite of soil particles that clump or bind together, giving soil its structure. Soil that is aggregated in larger particles is less prone to being eroded by the wind. And soils with more organic matter also benefit the climate, by storing more carbon.
While these principles have long been known, many irrigated crops still rely on tillage. There are a range of reasons for this, including historical systems that have relied on tillage, concerns about planting and weed management, and other real and perceived challenges. However, there are a growing number of irrigated producers who are developing viable alternatives, and I had the privilege of profiling a few of these individuals in my case study work. In the Columbia Basin, Lorin Grigg and his father have developed a strip tillage strategy that includes a cover crop, reduces wind erosion and protects onion and corn seedlings during the spring. They have used this strategy to grow onions for many years, protecting the farm’s fine sandy soils from wind erosion, particularly during windy conditions in the spring and fall.
While this strategy benefits the climate, it has also had direct economic benefits for the Griggs. In the spring, windblown sand can also destroy young seedlings. When this happens, farmers have to replant at significant expense, or, if the planting window for the primary crop has passed, convert to another, generally less profitable, crop. Sand-blasting is particularly risky for onions, because seed is small, expensive, and slow-growing. In this context, strip tillage acts as a form of insurance that reduces the risk of losing onion seedlings. As Lorin says, “Once in a while we may not have a windy spring, but most of the years it’s very windy here. If I put a cover crop in, I’m pretty much guaranteed that I can sleep at night and let the wind blow and not have to turn the water on” (wet soil is not easy for the wind to carry).
Big Biomass and More Often; A Green Manure Frequency Hypothesis
In a previous post, I argued that green manures require big biomass to achieve benefits that outweigh the damage done by tilling the crop into the soil. This is the point-in-time need, but what about over time? I believe that some benefits of green manures are cumulative, they build on the changes that the previous green manure crop made. To get this cumulative effect, the green manures must be close enough in time so that the changes from one crop have not dissipated before the next green manure crop is used. So, the crucial factors may be both the biomass produced by a green manure crop AND how often you produce that biomass in a field.
Here is my hypothesis for why frequency, along with biomass, is a key factor in this system:
My example system is potatoes following mustard green manure crops, but the same idea may be effective in other systems. You can read a case study of a farmer in this system published in June 2017.
A mustard green manure, when incorporated, increases the soil’s ability to suppress a pest. Here the pest is the disease/nematode complex “potato early dying.” However, the suppression effect is not permanent; it increases to a certain level but after time decreases as the green manure effects on the soil fade.
The pest pressure in the field is also important, shown here as A or B. If the pest suppression ability, related directly to green manure biomass and perhaps incorporation methods, rises above the disease level, then we see suppression, but if not, no suppression even though we have changed the soil. So higher pest pressures may mask the changes of one green manure crop.
A and B could also represent the use of a potato cultivar that is more or less resistant to potato early dying. Line A would be a less resistant cultivar needing a higher level of suppression in the soil, while a more resistant cultivar, line B, would not need as much suppression.
In a 4-year rotation (Figure 1a), where green manures are only used before potatoes, the level of pest suppression may fade to pre-green manure levels after 2+ years without a green manures. In this case, the second green manure crop gives results similar to the first crop. There would be no cumulative effect.
Now consider what could happen if we come back with another green manure crop before the increased pest suppression level dropped back to pre-green manure levels (Figure 1b). The peak level of pest suppression would surpass that from the first green manure crop. If continued, the cumulative effect would continue to increase pest suppression levels in the soil.
A good hypothesis can explain observations. When I first had this idea about cumulative effects, I liked it because it would account for the results I have seen in the field. Those using their first green manure crop generally do not see much pest suppression, although they still improve their soils. Even those who persevered in using mustard green manures did not find the success we were measuring at the Gies farm (McGuire 2003). The difference? At the time of our first testing of the Gies fields, the soils had received the benefit of 3-4 green manure crops, each separated by just one year of potatoes. All the other growers were using at least a 3-yr rotation and sometimes longer. These counterintuitive benefits we see in a shorter crop rotation could be explained if the pest suppression ability of the soil is cumulative when green manures are grown more often.
There are some potential problems with doing this on farms. Pests that are not affected by the green manure may get worse in a short rotation; however, this was not evident on the Gies farm fields. Also, potato processors stipulate the length of the crop rotation in their contracts with potato farmers. They would have to be convinced of the benefits of shorter rotations with green manures before they will change this.
However, there are also some potential benefits. Growing potatoes more often should increase profits if yield and quality can be maintained. Farmers doing this could concentrate potato production on their best fields, leaving other less productive fields to less-valuable crops. Eventually, as pest suppression in the soil builds, fumigation could be eliminated which would also increase profits. In addition to profits, the soil under the shorter rotations should improve as we saw in the Gies fields.
So, what’s next? Testing this hypothesis through on-farm research is feasible with support from farmers and processors – the field setup and work required is not difficult. It would, however, take a long-term effort to see how many green manure crops it takes to increase pest suppression on fields with different soil types and crop history. Check back with me in 10 years.
McGuire, A.M. 2003. Mustard Green Manures Replace Fumigant and Improve Infiltration in Potato Cropping System. Crop management. doi: 10.1094/CM-2003-0822-01-RS.
New Video: Reduced Tillage in Organic Vegetable Production
Created by our own Doug Collins and his former graduate student, David Sullivan, this video covers the concept of reduced tillage organic agriculture, cover crop and weed management, and specialized equipment. Techniques and findings from recent research are shared to assist producers in trialing reduced tillage systems. It is intended for organic vegetable producers and agricultural professionals, especially in the maritime northwest. Check it out!
Without big biomass, green manures are a step backwards
Green manuring is the lesser-used option in cover cropping. Most cover crops are killed and left on the soil surface, but green manures are tilled into the soil. That is where they have their unique effects. They feed soil microbes and larger organisms and thus change the community composition to benefit crops that follow. This enlarged soil microbe community then produces more stable aggregates and better soil structure for overall increased soil function. However, for the benefits of green manures to outweigh the tillage required by the practice, a large amount of biomass must be grown.
Tillage breaks down aggregates, disturbs soil microbial communities, and quickens breakdown of organic matter. Biomass does the opposite. The more plant biomass incorporated into the soil, the more steps forward the soil takes to overcome the backward steps of tillage.
Big biomass also improves green manure’s effects on soilborne pests. Both suppression of pests by the chemicals in green manure crops (as with mustard) and general suppression of pests by the feeding of the existing microbe population will be increased by greater amounts of biomass (see Using Green Manures in Potato Cropping Systems)
Biomass = Sunlight + Temperature + Water + Weed Control + Nutrients
The key factors in producing biomass are time, temperature, water, and soil fertility. Sunshine falling on green plants when temperatures are conducive to plant growth is the basic currency of farmers. For profit they give cash crops the best days but parceling some of the summer heat to a green manure crop can give a green manure crop the boost it needs to produce big biomass. Days can make a difference. Consider this planting date study of a mustard green manure crop grown after wheat near Moses Lake, WA, in 2002.
A day or two in August is worth a week or more in mid- to late-September due to lower temperatures and reduced daylight hours. The same is true for the spring; overwintering legume green manures should be allowed to grow into May or June to give enough benefit to cover seed and planting costs.
Irrigation of green manure crops
Planting in August may be the best time for plant growth, but it is also the hottest, driest time of year in the arid West. Big biomass will not be possible without irrigation. Where water is expensive, the cost can be prohibitive. The timing of irrigation is also important; a green manure crop stressed for water will shift from vegetative to reproductive growth. The earlier bloom will reduce biomass production. The same goes for competition from weeds.
Ideally, weeds will be out-competed by a fast-growing green manure crop planted in a field with low weed pressure. However, planting after a cash crop like wheat, while allowing good sun and temperature for the green manure crop growth, also sets up the volunteer wheat crop to become a major weed. Volunteer wheat and other weeds reduce green manure biomass by stealing sunlight, water, and nutrients. To get big biomass, weeds must be controlled. If necessary, as with volunteer wheat, with a selective herbicide. Killing the volunteer wheat in a mustard green manure (see Mustard Green Manures) can also assist in controlling parasitic nematodes in potatoes (a crop that often follows green manure), as wheat is a good host for some of the nematodes.
Fertilizing green manure crops
Green manures are not the plant-it-and-hope-for-the-best variety of cover crops. Although that can work for crops planted only to protect the soil from erosion, the big biomass required to make green manures beneficial require high soil nutrient levels.
In his 1927 treatise “Green Manuring” Pieters recommends fertilizing green manure crops for success, “The green-manure crop should therefore be given mineral fertilizers when necessary, though unfortunately there is an idea that a soil-improving crop can take care of itself.”. He gives these reasons for doing this, which still apply
If you are applying only what the previous cash crop needs, then there will be little left over for the green manure crop.
Biomass is the key to green manure’s benefits; soil fertility, including fertilizer application, is the key to biomass.
More from Pieters, “The amount of fertilizer to apply will vary with conditions, but if it is desired to improve a poor soil, the green-manure crop should be liberally fertilized.”
Because of the tillage, big biomass is not an option with green manures. Biomass is not only important for individual crop’s benefits but may be important over time – more on green manure biomass frequency in a future post. If you are not going to manage the sunlight, temperature, water, and nutrients, you are better off planting a cover crop that will not be tilled into the soil.
This post is Part 2 of Green Manure series; read Part 1.
Pieters, A.J. 1927. Green manuring. John Wiley & Sons, NY.
Soils under corn and tallgrass prairie; research to challenge our assumptions
It is often thought that nature is diverse and that the move to agriculture reduces that diversity which results in reduced function, or ecosystem services. Here is a paper that tests this idea in the soil by comparing soil microbial populations in corn and never-cultivated native tallgrass prairie. The results are both expected and surprising.
What did they do?
In 2009, the researchers (Mackelprang et al. 2018) picked never-cultivated tallgrass prairie sites in Wisconsin, Iowa, and Kansas, and then found local corn fields that matched the texture, slope, aspect, and drainage of the prairie sites. They sampled the surface soil (~5” deep) of all the sites and then analyzed them. Using DNA extraction and gene sequencing, lipid analysis, and some complicated bioinformatic and statistical tools, they were able to estimate the number of different species in the soils, their populations, and how the function of the soils would be affected by their microbial makeup.
What did they find?
First, the expected result: microbial biomass was about double in the native prairie soil. The prairie soil is never tilled and has long-lived perennials with vigorous rooting systems; it should have more microbial biomass. We cannot expect agriculture, even no-till corn, with its annual crops to equal the native prairie. But microbial biomass does not tell us everything.
Here is the unexpected result: the soil microbial diversity, measured by the number of species, was higher in the corn soils than the prairie soils. Yes, higher in the corn. What about the idea that higher plant diversity drives higher microbial diversity in the soil? Well, at least in the tallgrass prairie, that idea will have to be reviewed. And it is not just this study. The paper cites two other research papers that found similar results. Why? Probably the nitrogen.
“Follow the nitrogen” is always a good idea when we are talking about plants, soil, natural ecosystems, or agriculture. It’s like “follow the money” for organisms other than humans. This is because, in natural ecosystems like the tallgrass prairie, production is often limited by nitrogen supply. As Vitousek et al. (2002) write “N limitation to primary production and other ecosystem processes is widespread.” This goes counter to a common narrative that goes something like this, “nature, through N-fixing organisms, fixes all the nitrogen it needs” and the corollary “if we farm like nature, agriculture will not need nitrogen fertilizer.” Our prairie researchers, Mackelprang et al. suggested that it was probably the addition of nitrogen fertilizer to the corn fields that promoted the higher diversity; “Ample provision of otherwise scarce nutrients, such as nitrogen and phosphorus could drive fertilizer-associated increases in diversity.”
One more result, this also unexpected. The researchers did what they called a “core functional gene analysis.” They looked through the genes they had sequenced from the soil for those related to several core functions in the soil: nutrient transport, cell regulation and signaling, response to osmotic stress (drought) and nitrogen and carbon cycling. The analysis showed that there were significant differences in both bacterial and fungal populations between the two soils. However, the differences did not seem to matter; the corn soil retained all the functions of the prairie soil. In their dry words, “…many functions are resilient to changes caused by land management practices.” Indeed.
What does this mean?
It means that popular ideas about biodiversity and its effects in nature and agriculture are often wrong, or at least incomplete. For example, Peralta et al. (2018) found that bacterial populations in soils under diverse crop rotations were less diverse than those under continuous corn. However, after 12 years, diverse rotations had more disease suppressive bacterial populations than the mono-cropped corn. A good take away from the Peralta paper: “The composition of the microbial community could be more important than diversity to disease suppressive function …”
Even ecologists are saying that we may have put too much value on diversity for diversity’s sake. In the blog post “Questioning the value of biodiversity” ecologist Jeremy Fox comments on a review of the book What’s So Good About Biodiversity?. Adair et al. (2018) had similar observations from looking at the effects of diversity on carbon storage in soils. “These new findings indicate that ecosystem scientists should shift away from treating biodiversity as an ASSUMED amplifier of key ecosystem services like carbon storage, and instead treat it as a subset of factors that influence such services,” (Adair quoted here, emphasis mine).
What all this calls for is a correction in our thinking. Except where we are talking about saving endangered species, diversity should be considered a means to some ends, not a universally beneficial end in itself.
Adair, Carol, E., D.U. Hooper, A. Paquette, and B.A. Hungate. 2018. Ecosystem context illuminates conflicting roles of plant diversity in carbon storage. Ecology Letters 0(0). doi: 10.1111/ele.13145.
Mackelprang, R., A.M. Grube, R. Lamendella, E. da C. Jesus, A. Copeland, C. Liang, R.D. Jackson, C.W. Rice, S. Kapucija, B. Parsa, S.G. Tringe, J.M. Tiedje, and J.K. Jansson. 2018. Microbial Community Structure and Functional Potential in Cultivated and Native Tallgrass Prairie Soils of the Midwestern United States. Front. Microbiol. 9. doi: 10.3389/fmicb.2018.01775.
Peralta, A.L., Y. Sun, M.D. McDaniel, and J.T. Lennon. 2018. Crop rotational diversity increases disease suppressive capacity of soil microbiomes. Ecosphere 9(5): e02235. doi: 10.1002/ecs2.2235.
Vitousek, P.M., K. Cassman, C. Cleveland, T. Crews, C.B. Field, N.B. Grimm, R.W. Howarth, R. Marino, L. Martinelli, E.B. Rastetter, and J.I. Sprent. 2002. Towards an ecological understanding of biological nitrogen fixation. Biogeochemistry 57–58(1): 1–45. doi: 10.1023/A:1015798428743.
BIOAg now seeking proposals
The 2019 BIOAg request for proposals is now available!
The goal of the BIOAg solicitation is to engage WSU faculty to advance the development, understanding, and use of biologically-intensive, organic and sustainable agriculture in Washington State. BIOAg funding can be requested for three purposes: to stimulate new research initiatives, to augment existing research to address critical gaps, and to move existing, game-changing research out into the real world.
Please read the RFP and application forms carefully; changes have been made from prior solicitations. The RFP is available on BIOAg Grant Program page.
Letter of intent are requested by Nov. 16th, and project proposals are due Dec. 14th.
Organic Ag Snapshot for 2017
Organic agriculture in Washington State, as with the rest of the country and world, experienced continued growth in 2017, as we documented in our latest report. New records were reached for certified farms and acres in the state, as well as for farmgate sales of organic products. Certified acres rose 3% to 110,000 acres, representing about 0.8% of the cropland in the state. There were 892 certified farms (2.3% of farms in the state), 29 farms registered for transition, and an uncounted number of exempt organic farms (sales less than $5,000 per year). Apples experienced the largest growth, up 36% to >22,000 acres. This remains the most prominent organic crop in the state economically, accounting for about 12% of all bearing apple acres in the state and over 90% of the fresh organic apple production in the U.S. The number of organic dairies also reached a new high of 50, with a record number of organic dairy cows. There were declines in acres of organic wheat, corn, dry bean, blueberry, snap bean, and potato acreage, while acres of organic corn silage, asparagus, green pea, pear, cherry, and mixed vegetables went up. Total organic farmgate sales were in excess of $667 million, a 2% growth that was slower than previous years perhaps due to lower organic apple prices. Grant County remained the leader in organic farms, acres, and sales statewide, while Skagit County was tops in western Washington for organic acres and sales. The central Washington irrigated area has the most transition acres and will continue as the dominant area for organic agriculture in the state.
BIOAg Funding Awards Announced
The BIOAg Grant Program is one critical way that the Center for Sustaining Agriculture and Natural Resources carries out its mission improve the environment, increase farm profitability, and improve the human sustainability of agriculture and the food system. We use this program to incubate research and educational activities at WSU that advance the sustainability of agriculture in the state – enabling WSU faculty and partners to leverage significant additional external support to advance these goals. In addition, the Program has supported a number of graduate students who have and will pursue careers in academia, industry and community leadership with a focus on agricultural sustainability.